This dude decides to stack a bunch of cubes on top of each other. He wants to figure out the number of visible faces on each tower. When you stack them up, the side faces are separate!!!!! (Ex. If you stacked 4 blocks, 4 faces would be visible on the side) Write an algebraic expression to show how the dude can figure out how many visible faces are in each stack (bottom one does not count, so 1 block would be 5 faces) :I